[Intel-gfx] [PATCH] drm/i915: add a tracepoint for gpu frequency changes

[Ben Widawsky]

On 2012-09-01 11:28, Arjan van de Ven wrote:
> On 9/1/2012 11:26 AM, Ben Widawsky wrote:
>> On 2012-08-30 04:26, Daniel Vetter wrote:
>>> We've had and still have too many issues where the gpu turbot 
>>> doesn't
>>> quite to what it's supposed to do (or what we want it to do).
>>>
>>> Adding a tracepoint to track when the desired gpu frequence changes
>>> should help a lot in characterizing and understanding problematic
>>> workloads.
>>>
>>> Also, this should be fairly interesting for power tuning (and
>>> especially noticing when the gpu is stuck in high frequencies, as 
>>> has
>>> happened in the past) and hence for integration into powertop and
>>> similar tools.
>>>
>>> Cc: Arjan van de Ven <arjan at linux.intel.com>
>>> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
>>
>> I can't help but think it's equally interesting to know when the 
>> queue the work as well.
>>
>>
>
> btw... if the userspace interface (e.g. the actual event) is not
> controversial and very unlikely to change,
> I'd like to start coding the powertop support for this already....

I have no problem with Daniel's patch. It's just a matter of cutting 
through some scheduler BS of "when the GPU wants to change frequency" 
vs. "when we actually change the GPU frequency." I think *both* are 
interesting.

-- 
Ben Widawsky, Intel Open Source Technology Center